The subject application is related to subject matter disclosed in Japanese Patent Applications No. H11-231740 filed on Aug. 18, 1999 and H11-255622 filed on Sep. 9, 1999 in Japan to which the subject application claims priority under Paris Convention and which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to an ink jet recording apparatus such as an ink jet printer or an ink jet plotter, particularly to a technique of performing temperature correction for drive conditions of a recording head.
2. Related Background Art
In a certain kind of recording head of an ink jet recording apparatus such as an ink jet printer or an ink jet plotter, there are a plurality of pressure generation elements such as piezoelectric vibrators (e.g., piezoelectric elements) corresponding to a plurality of nozzle openings, respectively. These pressure generation elements discharge ink droplets through the nozzle openings, when ink in a pressure generation chamber connected to the nozzle openings is pressurized.
In this type of ink jet recording apparatus, while the discharge of the ink is repeated, the recording head causes a temperature rise, so that an ink viscosity changes. As a result, an ink discharge amount fluctuates, thereby deteriorating a recording quality. Therefore, there has been taken a measure of detecting a temperature of the recording head and changing a drive waveform and a drive voltage on the basis of the temperature detection result, or another measure.
However, in a conventional temperature correction method of the ink jet recording apparatus, the recording head temperature is detected by every constant time, and an actual recording operation is not correlated with a temperature detection timing. Therefore, there is a problem that when a data transfer timing overlaps the temperature detection timing, the data transfer timing is delayed, so that a recording throughput has to be sacrificed.
Moreover, in the ink jet recording apparatus, not only an A4 sheet or another cut sheet, but also a rolled sheet or another continuous sheet are used as a recording medium, but in the conventional ink jet recording apparatus, the temperature correction of the recording head is not performed for each type of the recording sheet at an optimum timing.
Furthermore, temperature changes of the recording head include not only a temperature rise but also a temperature drop during discontinuance of discharging of the ink droplets, but with respect to the temperature drop, the conventional ink jet recording apparatus has a problem that no temperature correction is performed at an adequate timing.
In consideration of the aforementioned problems, an object of the present invention is to provide an ink jet recording apparatus and an ink jet recording method in which a recording head temperature is detected at a timing adapted for an actual recording operation, and a temperature correction is performed on the basis of the detection result, so that a recording head can be driven on optimum drive conditions.
To achieve the aforementioned object, there is provided an ink jet recording apparatus comprising:
a recording head in which when a plurality of pressure generation elements corresponding to a plurality of nozzle openings, respectively, pressurize ink in a pressure generation chamber connected to the nozzle openings, ink droplets are discharged to a recording medium via the nozzle opening;
temperature detection means for detecting a temperature of the recording head;
detection timing control means for allowing the temperature detection means to detect the temperature of the recording head at a predetermined timing;
temperature correction means for performing temperature correction for drive conditions of the recording head from the nozzle opening on the basis of a temperature detection result by the temperature detection means; and
recording stop monitor means for monitoring whether the discharging of the ink droplets is stopped or not.
On the basis of a monitor result of the recording stop monitor means, when the discharging of the ink droplets is stopped, the detection timing control means allows the temperature detection means to detect the temperature of the recording head until the discharging of the ink droplets starts.
According to the present invention, when the discharging of the ink droplets stops, the recording head temperature is detected and temperature correction is performed. Therefore, even when the recording head temperature drops by discontinuance of discharging of the ink droplets and the ink viscosity rises, ink droplet discharge conditions are corrected, so that viscosity changes are canceled out. Consequently, there is little likelihood that a weight of ink droplets fluctuates, and it is possible to perform recording with a high print quality.
Moreover, there is provided an ink jet recording apparatus comprising:
a recording head in which when a plurality of pressure generation elements corresponding to a plurality of nozzle openings, respectively, pressurize ink in a pressure generation chamber connected to the nozzle opening, ink droplets are discharged to a recording medium via the nozzle opening;
drive signal generation means for generating a drive signal to be applied to the pressure generation element;
temperature detection means for detecting a temperature of the recording head;
detection timing control means for allowing the temperature detection means to detect the temperature of the recording head at a predetermined timing; and
temperature correction means for performing temperature correction for drive conditions of the recording head on the basis of a temperature detection result by the temperature detection means.
The detection timing control means allows the temperature detection of the recording head to be performed every predetermined raster number.
Moreover, in the ink jet recording apparatus according to the present invention, for example, when recording is performed on an A4 cut sheet, time for feeding a sheet after finishing the recording of one page is utilized to allow the temperature detection means to detect the temperature.
In this manner, the temperature detection means can detect the temperature while avoiding the time for performing the recording operation and data transfer. Therefore, a processing for temperature correction does not prevent another printing operation, thereby improving recording throughput.